18x9.5" ET35 was not designed for use on the E9X M3, but it does technically work. The M3 is low offset both front and rear. With the right tire size the front will fit cleanly, but the rear will be very inboard. The rear will need 12-20mm spacers for proper fitment.

18x9.5" ET35 will just barely clear the strut tube with a 265/35/18 street tire. 275/35/18 would definitely touch the strut tube. R-componds would be even worse. The ideal offset for the E9X M3 is 22-25mm with a 9.5" wheel. We would recommend a 12mm front spacer when used with this wheel size. But this would result in having to spend money on a total of 4 spacers just to fit the wheels.

18x9.5" ET22 is the recommended size for the E9X M3. This can be used front and rear with a 275/35/18 tire with no issues, and no need for spacers.

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How about the rear with 18x10 square?

18x10" ET25 is a direct fitment both front and rear. No spacers are needed front or rear.

Thanks for the inputs, yes my 18x10ET25 square setup did not require spacer on fronts to clear strut. I thought the fronts stuck out much more than rears, and so placed the 10mm spacers on back instead. I have two track days on new setup and no problems to report. I'm running 35-38psi hot with -1.6 camber up front. I am planning to use the new Vorshlag camber plates as soon as they are available.